:> 1 : ] 



/' I | ! 



2*1 



ami til.- i-<|iiati..i. he system will differ 



i tins <tnl\ in tin- \alue 



the coiiriUnt term k. 



i meets the 



para (1) in two points 



an. I /', (v, //,), 



and the coordinate* of the 



iniililli- P /') 



*-**> "> /-***. . . 



Consigning (1) and (2) as simultaneous equations, and 

 eliminating j\ it follows that the ordinates of P l and P s are 

 roots of the equation 



t..,of y- 



Therefore, by A i 



y\ * y s 



o. 



(4) 



m - 



whatever the value of /b, the coordinates of the middle 

 he equat 



m 



here fore, the eqr, the diameter correspond- 



t he system of chords whose slope is m.* 



Equation (6) might have been obtained at onoe M a spreial fora of 

 [64 ], Art. 129, by giving appropriate Taloee to U coefBctenta A, B, 



;, and ('there need. 



